System, device, and method for detecting perturbations via a fiber optic sensor

ABSTRACT

Certain exemplary embodiments comprise a spatially distributed multimode optical fiber; a photodetector configured to detect optical signals provided from said fiber; a wireless digital module coupled to said photodetector and adapted to wirelessly transmit a wireless signal encoding a plurality of detected variables of the optical signals; a wireless receiver adapted to receive the wireless signal; and a signal processing module coupled to said wireless receiver and adapted to decode and interpret the plurality of detected variables of the optical signals.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to, and incorporates by reference inits entirety, pending U.S. Provisional Patent Application Ser. No.60/427,683, filed 18 Nov. 2002.

BRIEF DESCRIPTION OF THE DRAWINGS

A wide array of potential embodiments can be better understood throughthe following detailed description and the accompanying drawings inwhich:

FIG. 1 is a block diagram of an exemplary embodiment of a multimodefiber optic sensor;

FIG. 2 is a block diagram of an exemplary embodiment of an integratedmonitoring device;

FIG. 3 is a Fourier transform of data generated by a test subject lyingon her stomach in an exemplary embodiment of an integrated monitoringbed depicted in FIG. 2;

FIG. 4 is a side view of an exemplary embodiment of a multimode opticfiber;

FIG. 5 is a front view of a projection on a flat screen of an outputfrom the exemplary embodiment of FIG. 4;

FIG. 6 is a block diagram of an exemplary embodiment of a system 6000;

FIG. 7 is a block diagram of an exemplary embodiment of a system 7000;

FIG. 8 is a block diagram of an exemplary embodiment of a system 8000;

FIG. 9 is a block diagram of an exemplary embodiment of a system 9000;

FIG. 10 is a plot of power versus frequency data generated by anexemplary embodiment of the optical fiber sensor of FIG. 6;

FIG. 11 is a plot of power versus frequency data generated by anexemplary embodiment of the optical fiber sensor of FIG. 6;

FIG. 12 is a plot correlating calculated respiration rate vs. actualbreathing rate for data gathered via an exemplary embodiment of theoptical fiber sensor of FIG. 6;

FIG. 13 is a block diagram of an exemplary embodiment of a system 13000;

FIG. 14 is an exemplary user interface 14000 for a wireless opticalfiber speckle sensing system;

FIG. 15 is an exemplary user interface 15000;

FIG. 16 is an exemplary user interface 16000;

FIG. 17 is an exemplary user interface 17000;

FIG. 18 is an exemplary user interface 18000;

FIG. 19 is an exemplary user interface 19000;

FIG. 20 is an exemplary output data list 20000;

FIG. 21 is structural diagram of an exemplary software program 21000;

FIG. 22 is a flowchart of an exemplary embodiment of a method 22000;

FIG. 23 is a block diagram of an exemplary embodiment of an informationdevice 23000;

FIG. 24 is a plot of a power spectra of two exemplary perturbationdetections;

FIG. 25 is a plot of an exemplary time trace from an exemplaryembodiment of an SMS sensor;

FIG. 26 is a plot of a power spectra of the signal of FIG. 25;

FIG. 27 is a plot of an exemplary power spectra for different positions;

FIG. 28 is a plot of an exemplary time trace from an exemplaryembodiment of a HOME sensor; and

FIG. 29 is a plot of a power spectra of the signal of FIG. 28.

DEFINITIONS

When the following terms are used herein, the accompanying definitionsapply.

optical fiber—a filament of transparent dielectric material, usuallyglass or plastic, and usually circular in cross section, that guideslight. An optical fiber usually has a cylindrical core surrounded by,and in intimate contact with, a cladding of similar geometry. So thatthe light can be guided by the fiber, the refractive index of the coreis slightly different than that of the cladding.

fiber optic sensor—a device that utilizes an optical fiber as atransducer.

transducer—a device that converts one form of energy into another. Forexample, a sensing optical fiber can convert changes in mechanicalenergy, such as a perturbation of the fiber, to changes in opticalenergy.

mode—in a waveguide or cavity, one of the various possible patterns ofpropagating or standing electromagnetic fields. Each mode is typicallycharacterized by angle, frequency, polarization, electric fieldstrength, and/or magnetic field strength. For example, when a pulse oflight is transmitted through an optical fiber, the energy can follow anumber of paths that cross the fiber's longitudinal axis at differentangles. A group of paths that cross the axis at the same angle is knownas a mode.

lowest order mode—also known as the fundamental mode and the LP₀₁ mode,is the mode in which light passes through an optical fiber substantiallyparallel to the fiber's longitudinal axis.

high order mode—any mode other than the lowest order mode.

higher order mode—a mode having a higher angle of incidence with respectto the longitudinal axis of a fiber than a another, lower order, mode.

multimode—supporting the propagation of more than one mode. A multimodeoptical fiber may be either a graded-index (GI) fiber or a step-index(SI) fiber.

coherent—having waves with similar direction, amplitude, and phase thatare capable of exhibiting interference.

integrated—formed or united into a whole or into another entity.

integrating—providing the sum or total of; additive.

spatially distributed—arranged in a pre-determined pattern in a volume.

perturbation—a change in a physical system.

photodetector—a transducer capable of accepting an optical signal andproducing an electrical signal containing the same information as in theoptical signal. As used herein a photodetector can comprise aphotodiode, avalanche photodiode, PIN photodiode, photocell,photoelectric cell, photoconductor, CCD, and/or a CMOS device, etc.

photodetector array—a collection of photodetectors, typically arrangedin a gridlike pattern.

charge-coupled device (CCD)—a light-sensitive integrated circuit thatstores and displays the data for an image in such a way that each pixel(picture element) in the image is converted into an electrical chargethe intensity of which is related to a color in the color spectrum(which can be a black-and-white continuum). For a system supporting, forexample 65,535 colors, there will be a separate value for each colorthat can be stored and recovered. One of the two main types of imagesensors used in digital cameras. When a picture is taken, the CCD isstruck by light coming through the camera's lens. Each of the thousandsor millions of tiny pixels that make up the CCD convert this light intoelectrons. The number of electrons, usually described as the pixel'saccumulated charge, is measured, then converted to a digital value. Thislast step can occur outside the CCD, in a component called ananalog-to-digital converter.

complementary metal-oxide semiconductor (CMOS)—one of the two main typesof image sensors used in digital cameras. Its basic function is the sameas that of a CCD.

field emitter—a device that is fabricated on a sub-micron scale withlithography technique, and that emits electrons immediately when avoltage is applied.

digital camera—a camera that captures an image not on film, but in anelectronic imaging sensor that takes the place of film.

image—an at least two-dimensional representation of an object and/orphenomenon.

coupled—connected or linked by any known means, including mechanical,fluidic, acoustic, electrical, magnetic, optical, etc.

light pattern—a visible pattern, such as an interference pattern orspeckle, created by combined modes of light.

spatial—relating to an area or volume.

spatial filter—a device or method for ignoring, exposing, or detecting aspatial portion of an image and/or signal.

matched spatial filtering—filtering a spatial pattern to emphasize avariable of interest.

wireless—any data communication technique that utilizes electromagneticwaves emitted by an antenna to communicate data (i.e., via an unguidedmedium), including such data communication techniques as sonar, radio,cellular, cellular radio, digital cellular radio, ELF, LF, MF, HF, VHF,UHF, SEF, EHF, radar, microwave, satellite microwave, laser, infrared,etc., and specifically excluding human voice radio transmissions, thedata communication technique having a carrier frequency ranging fromabout 1 Hz to about 2×10¹⁴ Hz (about 200 teraHertz), including allvalues therebetween, such as for example, about 40 Hz, 6.010 kHz, 8.7MHz, 800 MHz, 2.4 GHz, 4.518 GHz, 30 GHz, etc. and including allsubranges therebetween, such as for example, from about 100 kHz to about100 MHz, about 30 MHz to about 1 GHz, about 3 kHz to about 300 GHz, etc.Wireless communications can include analog and/or digital data, signals,and/or transmissions.

signal—detectable transmitted energy that can be used to carryinformation. Operationally, a type of message, the text of whichconsists of one or more letters, words, characters, symbols, signalflags, visual displays, or special sounds, with prearranged meaning andwhich is conveyed or transmitted by visual, acoustical, or electricalmeans. The information in a signal can be, for example digitallyencrypted via for example, public key, PGP, and/or triple-DES, etc. Asanother example, the signal can be broadcast via, for example, aspread-spectrum technology such as, for example a frequency hopping or adirect-sequence spread-spectrum system.

signal processing module (signal processor)—a device for processing asignal. Signal processing activities can include formatting, sourceencoding, encrypting, channel encoding, multiplexing, modulating,frequency spreading, transmitting, receiving, frequency despreading,demodulating, sampling, detecting, demultiplexing, channel decoding,decrypting, source decoding, synchronization, analyzing, comparing,converting, transforming, Fourier transforming, interpreting,monitoring, and/or notifying, etc.

encode—to convert data by the use of a code, frequently one consistingof binary numbers, in such a manner that reconversion to the originalform is possible. Alternatively, to append redundant check symbols to amessage for the purpose of generating an error detection and/orcorrection code.

decode—to convert data by reversing the effect of previous encoding,and/or to interpret a code.

interpret—to make sense of and/or assign a meaning to.

vital sign—a physiological sign of life and usually an indicator of aperson's general physical condition. Vital signs can include movement,blood temperature, blood pressure, body temperature, pulse rate, and/orrespiratory rate, etc.

Publications

The following U.S. patents are hereby incorporated by reference hereinin their entirety:

-   -   20030095263 (Varshneya) “Fiber optic interferometric vital sign        monitor for use in magnetic resonance imaging, confined care        facilities and in-hospital”;    -   U.S. Pat. No. 6,498,652 (Varshneya) “Fiber optic monitor using        interferometry for detecting vital signs of a patient”;    -   U.S. Pat. No. 5,291,013 (Nafarrate) “Fiber optical monitor for        detecting normal breathing and heartbeat motion based on changes        in speckle patterns”;    -   U.S. Pat. No. 5,212,379 (Nafarrate) “Fiber optical monitor for        detecting motion based on changes in speckle patterns”;    -   U.S. Pat. No. 5,134,281 (Bryenton) “Microbend optic sensor with        fiber being sewn thereto in a sinuously looped disposition”;    -   U.S. Pat. No. 5,436,444 (Rawson) “Multimode optical fiber motion        monitor with audible output”;    -   U.S. Pat. No. 4,863,270 (Spillman) “Multi-mode optical fiber        sensor and method”;    -   U.S. Pat. No. 4,843,233 (Jeunhomme) “Device for detecting        vibrations including a multimode optical fiber as sensitive        element”; and    -   U.S. Pat. No. 4,297,684 (Butter) “Fiber optic intruder alarm        system”.

DETAILED DESCRIPTION

Certain exemplary embodiments provide a patient bed with integratedsensing, which can be useful for patient monitoring. The integratedmonitoring bed can automatically monitor patient movement, respirationrate, and/or pulse rate, etc. Certain exemplary embodiments can combinean interferomatic integrating fiber optic sensor, matched spatialfiltering to potentially optimize signal to noise ratio, a low costlaser pointer, a low cost digital camera, a computer such as a portablelaptop PC (or other information device), and/or software, etc.Monitoring patient movement can help determine whether externallyinduced changes of position might be useful to prevent the occurrence ofbedsores.

Certain exemplary embodiments provide a means, integrated into a patientbed, to monitor patient respiration rate, heart rate, and/or amount ofmovement in a continuous and nonintrusive manner. Certain exemplaryembodiments provide a monitoring carpet and/or pad that can be utilizedto monitor the physical activity of elderly patients and/or to alertcaregivers when potentially injurious events, such as falls, occur.

Certain exemplary embodiments can facilitate the automation of healthcare resulting in the potential reduction of certain medical errors.Certain exemplary embodiments can monitor movement of bed-riddenpatients thereby limiting the possibility of bedsores developing.Certain exemplary embodiments can monitor movement of an individual on acarpet or pad. If an individual does not move for a predetermined periodof time, certain exemplary embodiments permit automated notification ofthat fact.

A patient's vital signs can be monitored using periodic and/or intrusivemonitoring wherein a health care practitioner manually monitors patientsvital signs using separate monitoring equipment. With theever-increasing average age of the population and decreasing number ofnursing and other health care support personnel, it can be desirable toautomate biomedical measurements thereby freeing up medical staff toconcentrate on critical care. Certain automations can be achieved viause of optical fiber sensing technology.

When a pulse of light is transmitted through an optical fiber, theenergy can follow a number of paths that cross the fiber's longitudinalaxis at different angles. A group of paths that cross the axis at thesame angle is known as a mode. The lowest order mode, which is alsoknown as the fundamental mode and the LP₀₁ mode, is the mode in whichlight passes substantially parallel to the fiber axis. In modes otherthan the fundamental mode, known as high order modes, the light bouncesfrom one side to the other all the way down the fiber. Fibers that havebeen designed to support only one mode with minimal loss, thefundamental mode, are known as single mode fibers. A multi-mode fiber isa fiber whose design supports multiple modes, and typically supportsover 100 modes.

In certain exemplary embodiments, a monochromatic light source, such asa laser diode, can input coherent light into a multi-mode optical fibersegment that is subject to environmental perturbations. The coherentlight, as it travels through the core, can assume different modes,including a lowest order mode and at least one higher order mode. Thevarious modes can constructively and destructively interfere to producea characteristic speckle pattern that can be projected through a spatialfilter onto a photo-detector. In its simplest form, the spatial filtercan be defined by a light-blocking and/or light-absorbing sheet havingone or more apertures, such as circular holes, that pass a subset of thespeckle pattern to the photodetector. The signal output of thephotodetector can vary in response to the variation in the intensitydistribution of that portion of the speckle pattern passed to thephotodetector by the spatial filter. The output of the photodetector canbe provided to a signal processor with the change in the intensitydistribution functionally related to the sensed perturbations.

Certain sensing techniques for detecting changes in inter-modeinterference patterns in response to external environmentalperturbations are described in Spillman et al., “Statistical Mode Sensorfor Fiber Optic Vibration Sensing Applications”, Applied Optics 28, No.15, 3166–3176, 1989, which is incorporated herein by reference in itsentirety. Such sensing techniques are not believed to have beenpreviously used in an integrated monitoring system for monitoringpatients' vital signs.

Certain exemplary embodiments relate to an integrated monitoring bed formonitoring patient vital signs and/or activity level, and/or to anintegrated monitoring carpet/pad for monitoring patient vital signsand/or activity level.

In certain exemplary embodiments, the bed can utilize a sensingtechnique comprising a multimode fiber optic sensor. Optical energytransmitted through the core of an optical fiber, either a single ormulti-mode core, can be affected by physical perturbations of the fiber.The physical perturbation can alter the index of refraction of thecore-material and/or the differential indices between the cladding andthe core in such a way that the optical energy transmitted through thecore can be changed. The physical perturbation can be caused by tension-or compression-induced strain and/or strain induced by bending the fiberabout a small radius (i.e., micro-bending) or large radius bending(i.e., macro-bending). Accordingly, an optical fiber can be used as asensor to measure a physical parameter by correlating changes in theoutput energy with the environmental perturbations.

The energy output from the sensing fiber can be analyzed, for example,in terms of quantitative changes in intensity, wavelength, and/orpolarization states. In a more sophisticated context, the output lightcan be interferometrically compared against a reference source toprovide an interferometer pattern that can be empirically correlatedwith the fiber-perturbing parameter. In the interferometric context,e.g., a Mach-Zender interferometer, coherent source light can be passedthrough reference and sensing fibers with the light from the two pathscombined to form an interferometric pattern that can be analyzed toprovide information that is functionally related to an externalperturbation affecting the sensing fiber path.

Certain exemplary embodiments can provide a multi-mode optical fibersensor and/or method for measuring physical perturbations usinginterferometric parameter analysis of perturbation-affected lightpropagated through a multi-mode optical fiber. Certain exemplaryembodiments can provide a multi-mode optical fiber sensor and/or methodthat reduces the optical fiber requirements in an application byproviding a multi-function multi-mode optical fiber in which themeasurement of physical perturbations using interferometric parameteranalysis can be performed in conjunction with other functions, includingdata transmission, communications, control, and/or telemetry. Certainexemplary embodiments can provide a multi-mode optical fiber sensor andmethod in which coherent monochromatic radiation from a optical energysource passes through a multi-mode optical fiber that is subjected to anexternal perturbation. As the light is conducted through the core, thevarious modes can constructively and destructively interfere with oneanother with the projected output having a characteristic inter-modal“speckle” pattern. A detector, such as a two-dimensional staring array,can output an electrical signal in response to the intensitydistribution of the speckle pattern. As the fiber or a segment thereofis perturbed, the inter-modal interference pattern and/or the intensitydistribution can change in a manner functionally related to theperturbation. The corresponding output of the detector can be analyzedby a signal processor to provide a signal output representative of theperturbation.

In certain exemplary embodiments, the output light from the multi-modeoptical fiber can be projected onto a multi-pixel CCD array. As the CCDarray is scanned, its outputs can be sent to a signal processor thatconverts the individual pixel output into a corresponding digital valueand/or stores the digitized array output as two successive data frames.The absolute value of the change between corresponding pixel data pointsin the two data frames can be summed to provide a signal output that isfunctionally related to the sensed perturbations.

In certain exemplary embodiments, a fiber perturbation region or zonecan be defined in which the multi-mode fiber optic sensor is sensitiveto perturbation only within the defined region, for example, byproviding single mode input and output optical fiber with a intermediatemulti-mode optical fiber that is subjected to and senses theperturbations. The light can be output through a spatial filter and/orone or more lenses, such as a ¼ pitch gradient index rod lens, toanother multi-mode optical fiber segment that can carry the light to thephotodetector for processing.

Certain exemplary embodiments can provide a multi-mode optical fibersensor in which the constructive and destructive interference ofcoherent light in a multi-mode fiber provides optical information usefulin providing a signal that is functionally related to the sensedperturbation. Additionally, the sensing optical fiber can be used toalso transmit other data, such as communications, control, telemetry,etc., on wavelength bands outside that used to provide perturbationsensing to provide a multi-function optical fiber.

FIG. 1 is a block diagram of an exemplary embodiment of a multimodefiber optic sensor 1000. Light from a coherent light source 1100 can becoupled to a multimode optical fiber 1200. Light exiting fiber 1200 canform a complex speckle pattern due to intermodal interference. If fiber1200 is perturbed, such as by a perturbation F, fiber 1200 canexperience mechanical flexing and/or bending, which can cause thedistribution of power in the pattern to change but not the total power.In other words, some speckles decrease in power while others increase inpower during perturbation, but the total power is unaffected. Light canbe output from fiber 1200 and its speckle pattern can be sensed by to aphotodetector 1300, such as a photodetector array, a charge coupleddevice (CCD), complementary metal oxide semiconductor (CMOS) device,and/or a spatial detector array. Photodetector 1300 can generate asignal 1400, which can be processed by a signal processor 1500. Thesignal processor can sample the whole speckle pattern and/or any portionthereof, and/or can store any portion of the pre-sampled or sampledpattern in a memory device. The pattern can be sampled again and the sumof the absolute values of the intensity changes seen by the pixels ofthe array can be computed and/or output. The process can then berepeated.

If the integrated perturbation is symbolized as P, and time issymbolized as t, then it has been shown that fiber output isproportional to the absolute value of dP/dt or ΔP/Δt, such that for anysensor output at frequency w, the perturbation causing that output wouldbe at w/2. Such a fiber is sometimes referred to as a Statistical Mode(STM) sensor.

It has also been shown in Spillman and Huston, “Scaling and Antenna Gainin Integrating Fiber Optic Sensors”, Journal of Lightwave Technology 13,No. 7, 1222–1230, (1995), which is incorporated herein by references inits entirety, and in Huston et al., “Monitoring Microfloor Vibrationswith Distributed Fiber Optic Sensors”, Proc. SPEE 3671, 118–125, 1999,which is incorporated herein by reference in its entirety, that thesignal to noise ratio of an integrating sensor can be significantlyimproved by matching the spatial pattern of the integrating sensor tothe parameter field of interest (e.g., via matched filtering and/orpreprocessing). It has been discovered that the spatial distribution ofthe sensor can be matched to the distribution of displacement producedby, for example, respiration and/or heartbeat, thereby improving thesignal to noise ratio of the sensor.

FIG. 2 is a block diagram of an exemplary embodiment of an integratedmonitoring device 2000 that can comprise an STM sensor. Light from acoherent optical source 2100, such as a laser pointer, can be coupledinto a multimode optical fiber 2200, which can be held stationary by afirst mechanical fiber/source coupling element 2150. That portion offiber 2200 positioned between coupling element 2150 and a target region2320 of the bed 2300 can be contained within a first mechanical dampingelement 2220. The sensing region 2240 of fiber 2200 can be spatiallydistributed and/or configured in a pattern 2280 chosen to optimizeresponse to respiration, heart rate, and/or movement. For example, forrespiration, target region 2320 might be generally defined between anexpected position on bed 2300 of the shoulders of a patient and anexpected position on bed 2300 of the hips of the patient. Thus, sensingregion 2240 and/or pattern 2280 can be generally placed within, on,and/or adjacent, target region 2320. Pattern 2280 of sensing region 2240can be serpentine, spiral, irregularly meandering, etc., and can includeas many curves and/or turns as needed, and/or can be distributed over aslarge a percentage of target region 2320 as needed, to optimize responseto a targeted vital sign and/or other perturbation. Because the spatialdistribution of pattern 2280 and/or sensing region 2240 can be matchedto a targeted perturbation, pattern 2280 and/or sensing region 2240 offiber 2200 can be considered to be a spatial filter.

Fiber 2200 can enter a second mechanical damping element 2260 and canextend to a second mechanical coupling element 2450 that can hold an endof fiber 2200 in the appropriate stationary position to optimally excitea two dimensional photodetector array 2400, such as a digital camera.Individual pixel intensities then can be transmitted from photodetector2400 to a computer 2500, such as a laptop personal computer, forprocessing as indicated herein.

Fiber 2200, which can serve as a filter fiber-sensing element, canalternatively be disposed in a carpet or pad (not shown). Pattern 2280and/or sensing region 2240 of fiber 2200 can be determined by the needsof the application. The upper region (above the legs of a patient) of amonitoring bed can be the only target region 2320 covered by sensingregion 2240, or sensing region 2240 can cover the entire patient restingregion of a monitoring bed 2300. In certain exemplary embodiments, oneor more additional integrating fiber optic sensors can be added to theintegrated monitoring bed, if desired for additional sensitivity and/orto target other types of perturbations. Alternatively, the entire areaof a carpet or pad can correspond to target region 2320 according to thedesired application.

A number of experimental runs have been made with test subjects in thefour most typical sleep positions, i.e., on back, stomach, and left andright fetal positions. FIG. 3 is a plot 3000 of discrete Fouriertransformed data generated by a test subject lying on her stomach in anexemplary embodiment of an integrated monitoring bed depicted in FIG. 2and utilizing an STM sensor. The frequency axis has been corrected forthe fact that the sensor output produces signals at twice the frequencyof the perturbation. Although the system was not optimized when themeasurements were made as, with respect to FIG. 3, the sampling rate wastoo high, signals corresponding to both the respiratory rate 3100 andthe heart rate 3200 can be seen clearly.

In certain exemplary embodiments, any generic long gauge length sensor,fiber optic or otherwise, can be used as a perturbation sensor. In termsof fiber optic technology, some of the sensors that can be used can bebased on intermodal interference, mode angle shifting, single modepolarmetric shifts, single mode interferometers (Mach-Zheirder,Michaelson), microbending, arrays (serial) of Fabrey-Perot cavities,and/or arrays (serial) of Bragg gratings, etc.

Certain exemplary embodiments can utilize a sensor based on mode angleshifting, or a High Order Mode Excitation (HOME) sensor, which canoutput a signal that is proportional to a fiber perturbation. FIG. 4 isa side view of an exemplary embodiment of a fiber portion 4000 of such asensor, which can comprise a multimode optic fiber 4200, into whichlight 4100 is injected at a non-zero incidence angle β, as measured fromthe longitudinal axis L of the fiber. That is, rather than beingintroduced exactly parallel to longitudinal axis L, the light has aradial component as well. This means that the light output 4300 fromfiber 4200 will be in the shape of a cone, having a lighted portion 4320and an unlighted portion 4340. When fiber 4200 is perturbed however, themodes of the light can change, potentially shifting into higher ordermodes and/or lower order modes. Either type of shift can cause thedimensions and/or shape of lighted portion 4320 and/or unlighted portion4340 to change. Changes in dimensions and/or shape of lighted portion4320 and/or unlighted portion 4340 can be detected by a photodetector,such as a pixelated detector (e.g., digital camera, CCD detector, CMOSdetector, etc.) and/or a non-pixelated detector (e.g., a large areaphotodetector). Thus, a photodetector can be positioned, for example,within a circular area normally surrounded and bordered by an annuluscreated by higher order modes. The photodetector can detectperturbations that result in the excitation of, coupling of, and/orshifting to, lower order modes the light of which is incident within thecircular area.

FIG. 5 is a front view of an exemplary projection 5000 on a flat screen5100 of an output 4300 from the exemplary embodiment of FIG. 4.Projection 5000 can comprise an inner unlighted portion 5200, an outerunlighted portion 5300, and a lighted portion 5400. If the fiber iscircular in longitudinal cross-section and flat screen 5100 is orientedperpendicular to the longitudinal axis of the fiber, then unlightedportion 5200 can be circular and/or lighted portion 5400 can be annular.

When the fiber pattern on the monitoring bed is perturbed by motion dueto respiration or heartbeat, the inner radius and/or outer radius of theannulus changes, so that if a spatial filter is used that onlyintercepts a portion of the annular pattern of light and allows it topass to a detector, an output signal will result containing informationabout the perturbation. For example, assuming that the outer radius ofthe annulus increases due to a perturbation, if a spatial filter onlypasses light that intercepts at least a portion of the area defined onlyby the increased outer radius, then the fact of the perturbation can besensed. That is, the spatial filter can pass light that falls within asector defined between the pre-perturbation outer circumference and theperturbation-caused outer circumference. Likewise if the perturbationdecreases a radius, diameter, and/or circumference of the annulus, thespatial filter and/or signal processor can detect the resulting changein the projected light pattern and/or intensity.

FIG. 6 is a block diagram of an exemplary embodiment of a system 6000that comprises a HOME sensor. In FIG. 6, an optical fiber 6100 canoutput a light pattern 6200, such as a speckle pattern, which can beprojected onto and through a spatial filter 6300 onto a photodetector6400. The spatial filter 6300, in a simple physical form, can befabricated from a opaque sheet having one or more apertures so that aportion of the speckle pattern, indicated generally at 6250, is blockedand a portion or subset 6270 thereof is allowed to pass to thephotodetector 6400. Assuming a constant light input to fiber 6100, theintensity of the total circular speckle pattern 6200 remainssubstantially constant over time, even when fiber 6100 is perturbed,because the average increase in intensity of some of the speckles willbe statistically averaged with the average decrease in intensity ofother of the speckles. Accordingly, the spatial filter 6300 can functionto expose only a portion or subset of the speckle pattern 6200 to thephotodetector 6400, so that a change in intensity can be detected. Ingeneral, the subset of the speckle pattern 6200 provided by the spatialfilter 6300 to the photodetector 6400 can be sufficiently large so thatan adequate signal-to-noise ratio is obtained and sufficiently small sothat statistical averaging effects do not prevent discrimination of theperturbation effect in the speckle pattern 6200. The shape of theaperture of the spatial filter 6300 is shown in FIG. 6 as an annularopening 6350, although the shape of the aperture or apertures in thespatial filter 6300 may be varied, such as for example, to form apredetermined rectangular matrix of circular holes. The photodetector6400 can output an electrical signal in response to the intensity of thesubset 6270 of speckle pattern 6200 imaged onto the photodetector 6400through the spatial filter 6300 so that variations in the intensity willprovide a corresponding output.

A signal processor 6500 can accept the output of the photodetector 6400and processes the signal to obtain an information signal functionallyrelated to the perturbation. Since any movement of optical fiber segment6100 can cause a change in the intensity of the speckle pattern 6200imaged onto the photodetector 6400, the movement of optical fibersegment 6100 can cause a corresponding change in the signal output ofthe photodetector 6400. The processing provided by signal processor 6500can include any of formatting, source encoding, encrypting, channelencoding, multiplexing, modulating, frequency spreading, transmitting,receiving, frequency despreading, demodulating, sampling, detecting,demultiplexing, channel decoding, decrypting, source decoding,synchronization, analyzing, comparing, converting, transforming, Fouriertransforming, interpreting, monitoring, and/or notifying, etc.

FIG. 7 is a block diagram of an exemplary embodiment of an STM and/orHOME system 7000. As shown, an optical source 7100 can couple coherentradiation into a single-mode optical fiber segment 7200 that is coupledat 7250 to a multi-mode optical fiber 7300 that is subjected to theperturbations F to be sensed, thereby reducing error from undesiredvibrations. After the desired perturbation F has been sensed by themulti-mode optical fiber segment 7300, the complex interference patternis output from the multi-mode optical fiber segment 7300 through aspatial filter 7400. A subset of the complex interference patter passesthrough the spatial filter 7400 and is focused through a lens 7500 intoa multi-mode optical fiber segment 7600. The complex interferencepattern is transmitted along the multi-mode optical fiber segment 7600to a photodetector 7700, which outputs a signal in response to theintensity of the subset of the complex interference pattern passed bythe spatial filter 7400. The signal is output to a signal processor 7800for analysis in a manner analogous to that described above for theembodiment of FIG. 6.

FIG. 8 is a block diagram of an exemplary embodiment of a system 8000.As shown therein, coherent, monochromatic radiation can be provided to amulti-mode optical fiber segment 8100. The complex interference patternproduced by the optical fiber segment 8100 can be output onto a CCDarray 8200 as a characteristic speckle pattern 8300. The CCD array 8200can be located a sufficient distance from the output end of the opticalfiber segment 8100 so that a pixel on the CCD array 8200 is smaller thanan average speckle feature; each pixel thereafter can generate a signalin response to the intensity of radiation incident on that pixel.

A signal processor 8400 can accepts the output of the CCD array 8200 andcan analyze the information in a frame-by-frame manner with between afirst frame and its immediately preceding frame providing informationthat is functionally related to the perturbation. More specifically, theintensity of the energy sensed by each pixel of the CCD array 8200 canbe digitized by a digitizer 8420 and/or stored in a first frame buffer8430. This initial frame data can be transferred to a frame delay buffer8440, which can hold the frame data for a selected time period, asanother data frame is stored in the first data frame buffer 8430. Theinitial frame data in the frame delay buffer 8440 then can betransferred to the second data frame buffer 8450. Accordingly, apreceding (n−1)^(th) data frame can be held in the data frame buffer8450 and a subsequent n^(th) data frame can be held in the data framebuffer 8430. Each buffer can take the form of a conventional memory withmulti-bit memory locations that correspond to pixels in the CCD array8200. A differencing circuit 8460 then can compare the contents of thedata frame buffers 8430 and 8450 on a pixel-by-pixel basis and canconvert the intensity differences into corresponding absolute values byan absolute value circuit 8470, which circuit can include memorylocations that correspond to pixels of the CCD array 8200. Lastly, thechanges in intensities of the pixels of the CCD array 8200 can beaccumulated in a summing circuit 8480 to obtain a final value, which canbe output to a memory, a recording device, and/or a display. Assuccessive data frame differences are determined, the final value outputwill vary as the sensing fiber segment 8100 is perturbed. Thus, thesignal processor 8400 can precisely measure the perturbation of theoptical fiber segment 8100 by measuring the change in intensity of eachindividual speckle of the speckle pattern 8300 on the CCD array 8200.

As in the case of the embodiment of FIG. 8, a subset or portion of thespeckle pattern 8300 can be evaluated to provide informationfunctionally related to the perturbation. Although an physical spatialfilter can be employed in a manner analogous to that of FIG. 7, the samefunctional result can be obtained in the embodiment of FIG. 8 via avirtual spatial filter 8410 of signal processor 8400 that disregards ordoes not pass the output of a selected percentage and/or selectedspatial portion of the pixels of the CCD array 8200 so that statisticalaveraging will not affect the ability to discriminate perturbations inthe speckle pattern 8300.

FIG. 9 is a block diagram of an exemplary embodiment of a wirelessoptical fiber sensing system 9000, which can include two portions: aremote portion that can comprise a light source, sensing fiber, CCDcamera and wireless transmitter; and a local portion (not shown)composed of wireless receiver and processing laptop.

The remote portion can include a remote wireless module 9100. Externalto module 9100, an power source 9210, such as an alternating currentapproximately 110–120 volt power source, can provide electrical power toan alternating current to direct current adapter 9220, which can plug into module 9100 to provide direct current to the light source, camera9400, and/or wireless transmitter 9500.

Within module 9100, a direct current voltage regulator 9230 can regulatevoltage to about 2.5 volts, and provide current to a driver 9240 of anoptical source 9310, such as a laser diode. Light 9320 can be producedand emitted by optical source 9310. The optical output of optical source9310 can be coupled to a segment of sensing fiber 9350 via an FC matingsleeve 9330 and a bare fiber adapter 9340. Similarly, sensing fiber 9350can be mechanically coupled to module 9100 via bare fiber adapter 9360and FC mating sleeve 9370. Light 9380 output by fiber 9350 can bereceived by a CCD camera 9400. Sampled frames of the far-field specklesperceived by camera 9400 can be sent to the local portion through awireless transmitter 9500.

FIG. 10 is a plot 10000 of power versus frequency data generated by anexemplary embodiment of a HOME optical fiber sensor. The frequency datawas obtained via Fourier transform. The plot shows a peak 10100 at about11 cycles/minute, which corresponds to the respiration rate of thepatient.

FIG. 11 is a plot of power versus frequency data generated by anexemplary embodiment of a HOME optical fiber sensor. The frequency datawas obtained via Fourier transform. The plot shows a peak 11100 at about10–15 cycles/minute, which corresponds to the respiration rate of thepatient, and a peak at about 55–60 cycles/minute, which corresponds tothe heart rate of the patient. FIG. 12 is a plot correlating calculatedrespiration rate vs. actual respiration rate for data plotted in FIG.11.

FIG. 13 is a block diagram of an exemplary embodiment of a wirelessoptic fiber sensing system 13000. A light source 13100 can couplecoherent light to an optical fiber 13200 which is distributed in apredetermined pattern on, above, and/or adjacent a human supportstructure 13300, such as a bed, mattress, mattress pad, chair, seat,carpet, carpet pad, and/or floor, etc. In certain exemplary embodiments,the optical fiber can be a 200 micrometer core silica multimode opticalfiber arranged in two sinusoidal overlapping patterns arrangedorthogonal to each other so that the fiber in each pattern crosses thefiber in the other pattern at an angle of 90 degrees. The light sourcecan be, for example, a DIY laser pointer from Laser Magic Co. of CostaMesa, Calif., which can provide an output of 5 mW @ 645 nm. Output fromoptical fiber 13200 can be detected by a photodetector 13400 and anelectrical signal generated thereby can be provided to a wirelesstransmitter 13500, which can output an electro-magnetic signal 13550from a first zone 13600, such as a patient's room, to a second zone13700, such as a nurse's station. The photodetector and wirelesstransmitter can be provided as a module, such as for example a GrandTecRFC-3000 wireless CCD module (provided by GrandTec USA of Dallas, Tex.),potentially with an accompanying wireless receiver. The electromagneticsignal 13550, which can be transmitted at, for example, about 2.4 GHz,can be received by a wireless receiver 13800 and provided, for examplevia a USB 2.0 interface, to an information device 13900, which cancomprise a signal processor. The receiver, information device, and/orsignal processor can potentially handle signals from multiple sensorsand/or transmitters. The sampling rate can be, for example, about 30frames/second. The information device can run a software programdesigned for processing received signal and/or data encoded therein,calculating appropriate values, such as the Sum of Pixel Differences(SPD) values of adjacent frames, and rendering (i.e., makingperceptible) the SPD values in real time possibly in combination withthe received frames. The software program can be written in any computerlanguage or tool, such as Visual C++ 6.0 by Microsoft of Redmond, Wash.The software program can automatically load a default video source thatis coupled to the information device. The software program can saveand/or output the SPD values to a predetermined and/or user-specifieddrive and/or file. The saved file can be in any format, including text,Excel, etc. The software program can provide a graphical user interface.

FIG. 14 is an exemplary user interface 14000 for a wireless opticalfiber speckle sensing system. User interface 14000 can include a widevariety of user interface elements, such as an image 14100 of thedetected light incident upon the photodetector, the light received bythe signal processor, and/or the light processed by the signal processorafter filtering and/or preprocessing. Additional user interface elementscan include a video source feature and/or parameter button 14200, aframe indicator and/or control 14300, a Sum of Pixel Difference (SPD)indicator and/or control 14400, a maximum SPD indicator and/or control14500, an autoscale control 14600, an SPD scale indicator and/or control14700, and/or a plot 14800 of SPD intensity versus time and/or location,etc.

FIG. 15 is an exemplary user interface 15000 for advanced video sourcefeatures and/or parameters. User interface 15000 can include a widevariety of user interface elements, such as tabs 15100, 15200, 15300,15400 for switching between various groups of video source featuresand/or parameters. User interface 15000 also can include a videostandard indicator and/or control 15500, a maximum bandwidth indicatorand/or control 15600, a consumed bandwidth indicator 15700, a horizontaloffset indicator and/or control 15800, and/or a vertical offsetindicator and/or control 15900, etc.

FIG. 16 is an exemplary user interface 16000 for capture source featuresand/or parameters. User interface 16000 can include a wide variety ofuser interface elements, such as video device selector 16100 and/orvideo source indicator and/or control 16200.

FIG. 17 is an exemplary user interface 17000 for video device settings.User interface 17000 can include a wide variety of user interfaceelements, such as indicators, selectors, and/or controls for brightness17100, contrast 17200, hue 17300, saturation 17400, sharpness 17500,white balance 17600, gamma 17700, and/or backlighting 17800, etc.

FIG. 18 is an exemplary user interface 18000 for camera controls. Userinterface 18000 can include a wide variety of user interface elements,such as indicators, selectors, and/or controls for zoom 18100, focus18200, exposure 18300, iris 18400, tilt 18500, pan 18600, and/or roll18700, etc.

FIG. 19 is an exemplary user interface 19000 for stream settings. Userinterface 19000 can include a wide variety of user interface elements,such as indicators, selectors, and/or controls for resolution 19100,pixel depth and/or compression 19200, and/or size 19300, etc. FIG. 20 isan exemplary output data list 20000, which can display a plurality ofSPD values 20100. FIG. 21 is structural diagram of an exemplary softwareprogram 21000.

FIG. 22 is a flowchart of an exemplary embodiment of a method 22000. Atactivity 22100, an optical fiber is spatially distributed in apredetermined pattern for facilitating sensing of a predetermined typeof perturbation. For example, a fiber can be distributed on a bed in apattern that is known to facilitate sensing of a person leaving orentering the bed, a position of the person on the bed, whether theperson has rolled lately, a heartbeat of the person, and/or arespiration rate of the person, etc. A fiber can be distributed in apattern that is known to facilitate sensing of a target, such as aperson, animal, and/or vehicle, etc., entering an area and/or leavingthe area. A fiber can be distributed in a pattern that is known tofacilitate sensing of whether a perturbation is caused by a person, ananimal, or an object, etc., potentially by virtue of a weight, weightdistribution, and/or frequency of impact, etc. The presence of the fibercan be hidden and/or non-intrusive. The fiber can be rugged and/orimpervious to liquid contact.

At activity 22200, output of the fiber can be spatially filtered. Suchfiltering can occur optically and/or digitally. At activity 22300,output of the fiber, such as optical signals, can be detected. Atactivity 23400, the detected fiber output can be transmitted, such asvia an electromagnetic signal, such as a wireless signal. Prior totransmission, the detected output can be formatted, source encoded,encrypted, channel encoded, multiplexed, modulated, and/or frequencyspread, etc. At activity 23500, the transmitted signal can be received.The receiver can receive signals from multiple transmitters. Atactivities 23600 and 23700, the received signal can be processed, whichcan include frequency despreading, demodulating, sampling, holding,digitizing, detecting, demultiplexing, channel decoding, decrypting,source decoding, synchronization, spatial filtering, comparing, summing,calculating, interpreting, and/or analyzing the signal and/or variablesencoded therein. For example, the received signal can be processed todetermine intensity, power, voltage, current, phase, and/or frequencyvalues, and/or changes therein. Via time division, frequency division,code division, phase division, and/or other division techniques formultiple access and/or multiplexing, multiple signals can be received bya single receiver and/or processed by a single signal processor. Becausea least certain such values of the signal can vary with time,particularly due to perturbations of the sensing fiber, at activity22800, the signal, variable values, and/or received data can becontinuously and monitored for statistically significant deviations frompredetermined values and/or limits. At activity 22900, a notificationcan be provided if a deviation is detected. The notification can beprovided by any technique and can be in any form. For example, a warningnotification can be provided to a nurse if a patient has been immobilefor too long and needs to be turned to prevent the formation of bedsores. As another example, a warning can be provided if motion isdetected when, where, and/or to an extent not expected, such as forexample, if the force, impact, and/or acceleration, etc., of a fallenpatient, an intruder, an overweight truck approaching a bridge, seismicmovement, and/or vibration, etc., is detected. Any or all detected,processed, monitored, and/or notification data can be logged. Thus, if anotification is provided to a nurse to turn a patient, the system canalso log that the turn occurred, thereby providing a validation recordof the movement to limit and/or avoid potential liability.

FIG. 23 is a block diagram of an exemplary embodiment of an informationdevice 23000, which can represent any of information device describedherein, such as information device 13900 of FIG. 13. Information device23000 includes any of numerous well-known components, such as forexample, one or more network interfaces 23100, one or more processors23200, one or more memories 23300 containing instructions 23400, and/orone or more input/output (I/O) devices 23500, etc. Via one or more I/Odevices 23500, a user interface 23600 can be provided.

As used herein, the term “information device” means any device capableof processing information, such as any general purpose and/or specialpurpose computer, such as a personal computer, workstation, server,minicomputer, mainframe, supercomputer, computer terminal, laptop,wearable computer, and/or Personal Digital Assistant (PDA), mobileterminal, Bluetooth device, communicator, “smart” phone (such as aHandspring Treo-like device), messaging service (e.g., Blackberry)receiver, pager, facsimile, cellular telephone, a traditional telephone,telephonic device, a programmed microprocessor or microcontroller and/orperipheral integrated circuit elements, an ASIC or other integratedcircuit, a hardware electronic logic circuit such as a discrete elementcircuit, and/or a programmable logic device such as a PLD, PLA, FPGA, orPAL, or the like, etc. In general any device on which resides a finitestate machine capable of implementing at least a portion of a method,structure, and/or or graphical user interface described herein may beused as an information device. An information device can includewell-known components such as one or more network interfaces, one ormore processors, one or more memories containing instructions, and/orone or more input/output (I/O) devices, one or more user interfaces,etc.

As used herein, the term “network interface” means any device, system,or subsystem capable of coupling an information device to a network. Forexample, a network interface can be a telephone, cellular phone,cellular modem, telephone data modem, fax modem, wireless transceiver,ethernet card, cable modem, digital subscriber line interface, bridge,hub, router, or other similar device.

As used herein, the term “processor” means a device for processingmachine-readable instruction. A processor can be a central processingunit, a local processor, a remote processor, parallel processors, and/ordistributed processors, etc. The processor can be a general-purposemicroprocessor, such the Pentium III series of microprocessorsmanufactured by the Intel Corporation of Santa Clara, Calif. In anotherembodiment, the processor can be an Application Specific IntegratedCircuit (ASIC) or a Field Programmable Gate Array (FPGA) that has beendesigned to implement in its hardware and/or firmware at least a part ofan embodiment disclosed herein.

As used herein, a “memory device” means any hardware element capable ofdata storage, such as for example, a non-volatile memory, volatilememory, Random Access Memory, RAM, Read Only Memory, ROM, flash memory,magnetic media, a hard disk, a floppy disk, a magnetic tape, an opticalmedia, an optical disk, a compact disk, a CD, a digital versatile disk,a DVD, and/or a raid array, etc.

As used herein, the term “firmware” means machine-readable instructionsthat are stored in a read-only memory (ROM). ROM's can comprise PROMsand EPROMs.

As used herein, the term “I/O device” means any sensory-oriented inputand/or output device, such as an audio, visual, haptic, olfactory,and/or taste-oriented device, including, for example, a monitor,display, projector, overhead display, keyboard, keypad, mouse,trackball, joystick, gamepad, wheel, touchpad, touch panel, pointingdevice, microphone, speaker, video camera, camera, scanner, printer,haptic device, vibrator, tactile simulator, and/or tactile pad,potentially including a port to which an I/O device can be attached orconnected.

As used herein, the term “haptic” means both the human sense ofkinesthetic movement and the human sense of touch. Among the manypotential haptic experiences are numerous sensations, body-positionaldifferences in sensations, and time-based changes in sensations that areperceived at least partially in non-visual, non-audible, andnon-olfactory manners, including the experiences of tactile touch (beingtouched), active touch, grasping, pressure, friction, traction, slip,stretch, force, torque, impact, puncture, vibration, motion,acceleration, jerk, pulse, orientation, limb position, gravity, texture,gap, recess, viscosity, pain, itch, moisture, temperature, thermalconductivity, and thermal capacity.

As used herein, the term “user interface” means any device for renderinginformation to a user and/or requesting information from the user. Auser interface includes at least one of textual, graphical, audio,video, animation, and/or haptic elements. A textual element can beprovided, for example, by a printer, monitor, display, projector, etc. Agraphical element can be provided, for example, via a monitor, display,projector, and/or visual indication device, such as a light, flag,beacon, etc. An audio element can be provided, for example, via aspeaker, microphone, and/or other sound generating and/or receivingdevice. A video element or animation element can be provided, forexample, via a monitor, display, projector, and/or other visual device.A haptic element can be provided, for example, via a very low frequencyspeaker, vibrator, tactile stimulator, tactile pad, simulator, keyboard,keypad, mouse, trackball, joystick, gamepad, wheel, touchpad, touchpanel, pointing device, and/or other haptic device, etc.

A user interface can include one or more textual elements such as, forexample, one or more letters, number, symbols, etc. A user interface caninclude one or more graphical elements such as, for example, an image,photograph, drawing, icon, window, title bar, panel, sheet, tab, drawer,matrix, table, form, calendar, outline view, frame, dialog box, statictext, text box, list, pick list, pop-up list, pull-down list, menu, toolbar, dock, check box, radio button, hyperlink, browser, button, control,palette, preview panel, color wheel, dial, slider, scroll bar, cursor,status bar, stepper, and/or progress indicator, etc. A textual and/orgraphical element can be used for selecting, programming, adjusting,changing, specifying, etc. an appearance, background color, backgroundstyle, border style, border thickness, foreground color, font, fontstyle, font size, alignment, line spacing, indent, maximum data length,validation, query, cursor type, pointer type, autosizing, position,and/or dimension, etc. A user interface can include one or more audioelements such as, for example, a volume control, pitch control, speedcontrol, voice selector, and/or one or more elements for controllingaudio play, speed, pause, fast forward, reverse, etc. A user interfacecan include one or more video elements such as, for example, elementscontrolling video play, speed, pause, fast forward, reverse, zoom-in,zoom-out, rotate, and/or tilt, etc. A user interface can include one ormore animation elements such as, for example, elements controllinganimation play, pause, fast forward, reverse, zoom-in, zoom-out, rotate,tilt, color, intensity, speed, frequency, appearance, etc. A userinterface can include one or more haptic elements such as, for example,elements utilizing tactile stimulus, force, pressure, vibration, motion,displacement, temperature, etc.

In certain exemplary embodiments, via one or more user interfaces 23600,a user can specify, input, view, locate, store, output, manipulate,and/or control, data, variables, parameters, and/or commands related toan operation of an optical sensing system, such as described herein.

We analyzed the applicability of these two techniques for simultaneouslydetecting patient movement, respiration and heart rate. The perturbationdue to respiration and heart rate was modeled as the sum of two cosinefunctions with the second cosine having an amplitude of 0.1 of theamplitude of the first. The discrete Fourier transform of this modeledsignal and the transform of the absolute value of the first derivativeof the signal is shown in FIG. 24. As can be seen, the modeled SMS powerspectra (fine line) clearly shows the first perturbation (at twice itsfrequency due to the taking of absolute value) but does not show thesecond perturbation due to complications from this type of processing.The HOME signal, on the other hand, clearly shows the peaks due to bothperturbations at their correct frequencies. The SMS approach allowsdetection of respiration and heart rate and is more sensitive than theHOME approach, but the HOME approach introduces less distortion due toprocessing and should allow better signal discrimination.

A number of experimental runs were conducted using both the SMS and HOMEsensors. A typical time trace from the SMS sensor is shown in FIG. 25while its Fourier transform is shown in FIG. 26. FIG. 27 shows how theresults vary for patients in different typical sleep positions: on back,on stomach, left fetal and right fetal. The signal peaks are at twicethe respiration rate as expected.

A typical time trace using the HOME sensor is shown in FIG. 28, and itspower spectrum is shown in FIG. 29. FIG. 11 shows the power spectrumfrom the HOME sensor when the test subject held his breath for 0.5 ofthe measurement period. This allowed the heart rate signal to be clearlydiscerned. Finally, FIG. 12 displays the measured (via the peak in thepower spectrum) vs the actual (as determined by patient counting)respiration rates using the HOME sensor.

As can be seen from these results, both the SMS and HOME sensors can beused to detect patient movement and respiration. Only the HOME sensor,however, demonstrated the ability to detect heart rate in thisexperiment. The SMS sensor, by the nature of its transduction process,will not become saturated, i.e. because it takes the derivative of asignal. The size of the DC component does not affect the sensitivity ofthis signal processing method. It can therefore detect patient movementand give repeatable results somewhat independently of patient weight.The HOME sensor, on the other hand, could be saturated by perturbationslarge enough to cause the available propagating mode volume to becomecompletely filled. Both sensors can be low cost, PC compatible, and canbe integrated into larger wireless systems.

Still other embodiments will become readily apparent to those skilled inthis art from reading the above-recited detailed description anddrawings of certain exemplary embodiments. It should be understood thatnumerous variations, modifications, and additional embodiments arepossible, and accordingly, all such variations, modifications, andembodiments are to be regarded as being within the spirit and scope ofthe appended claims. For example, regardless of the content of anyportion (e.g., title, field, background, summary, abstract, drawingfigure, etc.) of this application, unless clearly specified to thecontrary, there is no requirement for the inclusion in any claim of theapplication of any particular described or illustrated activity orelement, any particular sequence of such activities, or any particularinterrelationship of such elements. Moreover, any activity can berepeated, any activity can be performed by multiple entities, and/or anyelement can be duplicated. Further, any activity or element can beexcluded, the sequence of activities can vary, and/or theinterrelationship of elements can vary. Accordingly, the descriptionsand drawings are to be regarded as illustrative in nature, and not asrestrictive. Moreover, when any number or range is described herein,unless clearly stated otherwise, that number or range is approximate.When any range is described herein, unless clearly stated otherwise,that range includes all values therein and all subranges therein. Anyinformation in any material (e.g., a United States patent, United Statespatent application, book, article, etc.) that has been incorporated byreference herein, is only incorporated by reference to the extent thatno conflict exists between such information and the other statements anddrawings set forth herein. In the event of such conflict, including aconflict that would render a claim invalid, then any such conflictinginformation in such incorporated by reference material is specificallynot incorporated by reference herein.

1. A system, comprising: a spatially distributed multimode opticalfiber; a photodetector configured to detect optical signals providedfrom said fiber; a wireless digital module coupled to said photodetectorand adapted to wirelessly transmit a wireless signal encoding aplurality of detected variables of the optical signals; a wirelessreceiver adapted to receive the wireless signal; and a signal processingmodule coupled to said wireless receiver and adapted to decode andinterpret the plurality of detected variables of the optical signals. 2.The system of claim 1, further comprising a coherent optical sourceoptically couplable to said optical fiber.
 3. The system of claim 1,further comprising a laser diode optically couplable to said opticalfiber.
 4. The system of claim 1, further comprising a laser lightpointer optically couplable to said fiber.
 5. The system of claim 1,further comprising an electronic driver adapted to control lightprovided to said fiber.
 6. The system of claim 1, wherein said fiber isintegrating.
 7. The system of claim 1, wherein said fiber is spatiallydistributed with respect to a patient bed for optimized detection ofpatient movement.
 8. The system of claim 1, wherein said fiber isspatially distributed with respect to a patient bed for optimizeddetection of patient respiration.
 9. The system of claim 1, wherein saidfiber is spatially distributed with respect to a patient bed foroptimized detection of patient heart rate.
 10. The system of claim 1,wherein said fiber is spatially distributed with respect to a patientbed for optimized detection of any combination of patient movement,respiration rate, and heart rate.
 11. The system of claim 1, whereinsaid fiber converts higher order modes to lower order modes.
 12. Thesystem of claim 1, wherein said fiber converts lower order modes tohigher order modes.
 13. The system of claim 1, wherein the opticalsignals comprise a speckle pattern.
 14. The system of claim 1, whereinthe optical signals comprise a plurality of high order excitation modes.15. The system of claim 1, wherein the optical signals comprise aplurality of high order excitation modes that are proportional to aperturbation along said fiber.
 16. The system of claim 1, wherein saidphotodetector is optically couplable to said optical fiber.
 17. Thesystem of claim 1, wherein said photodetector provides an outputproportional an integrated perturbation along said fiber.
 18. The systemof claim 1, wherein said photodetector comprises a photodetector array.19. The system of claim 1, wherein said photodetector comprises adigital photodetector.
 20. The system of claim 1, wherein saidphotodetector comprises a digital photodetector array.
 21. The system ofclaim 1, wherein said photodetector comprises a CCD camera.
 22. Thesystem of claim 1, wherein said photodetector comprises a CMOS camera.23. The system of claim 1, wherein the wireless signal encodes aplurality of digitized images of the optical signals.
 24. The system ofclaim 1, further comprising a high order mode transmission elementoptically couplable to said optical fiber.
 25. The system of claim 1,further comprising a filter configured to pass only lower order modesconverted from higher order modes.
 26. The system of claim 1, furthercomprising a filter configured to pass only higher order modes convertedfrom lower order modes.
 27. The system of claim 1, further comprising amatched spatial filter.
 28. The system of claim 1, further comprising amatched spatial filter adapted to spatially filter light provided tosaid fiber.
 29. The system of claim 1, further comprising a matchedspatial filter adapted to filter the optical signals.
 30. The system ofclaim 1, further comprising a matched spatial filter adapted tospatially filter the plurality of detected variables of the opticalsignals.
 31. The system of claim 1, further comprising a matched spatialfilter adapted to filter a plurality of digitized images provided bysaid photodetector.
 32. The system of claim 1, wherein said signalprocessing module is adapted to decode a plurality of digitized imagesand to interpret one or more variables of the plurality of digitizedimages.
 33. The system of claim 1, wherein said signal processing moduleprovides an output proportional to an absolute value of ΔP/Δt, where Pis an integrated perturbation along said fiber and t is time.
 34. Thesystem of claim 1, wherein said signal processing module is adapted toprovide matched spatial filtering of a plurality of digitized images tooptimize a signal-to-noise ratio.
 35. The system of claim 1, whereinsaid signal processing module is adapted to process a predeterminedportion of the optical signals.
 36. The system of claim 1, wherein saidsignal processing module is adapted to process a portion of the opticalsignals, the portion associated with a human vital sign.
 37. The systemof claim 1, wherein said signal processing module is adapted tointerpret a frequency of a perturbation of the fiber.
 38. The system ofclaim 1, wherein said signal processing module is adapted to interpret afrequency of a perturbation of the plurality of detected variables. 39.The system of claim 1, wherein said signal processing module is adaptedto interpret fluctuations in a speckle pattern of the optical signals.40. The system of claim 1, wherein said signal processing module isadapted to interpret a conversion of excitation modes of the opticalsignals in a spatially filtered region.
 41. The system of claim 1,wherein said signal processing module is adapted to interpret anincidence of lower order excitation modes of the optical signals in apredetermined spatial region.
 42. The system of claim 1, wherein saidsignal processing module is adapted to interpret an incidence of highorder excitation modes of the optical signals in a predetermined spatialregion.
 43. The system of claim 1, wherein said signal processing moduleis adapted to interpret a frequency of a perturbation of the pluralityof detected variables, the frequency corresponding to a patient vitalsign.
 44. The system of claim 1, wherein said signal processing moduleis adapted to interpret a frequency of a perturbation of the pluralityof detected variables, the frequency corresponding to a patientmovement.
 45. The system of claim 1, wherein said signal processingmodule is adapted to interpret a change in an optical power of theplurality of detected variables.
 46. The system of claim 1, wherein saidsignal processing module is adapted to interpret a change in angle of anexcitation mode of the optical signals.
 47. The system of claim 1,wherein said signal processing module is adapted to interpret a changein excitation modes of the optical signals.
 48. The system of claim 1,wherein said signal processing module is adapted to monitor theplurality of detected variables of the for a change in a patient's vitalsign.
 49. The system of claim 1, wherein said signal processing moduleis adapted to monitor the plurality of detected variables for a changein a patient's movement.
 50. The system of claim 1, wherein said signalprocessing module is adapted to automatically monitor the plurality ofdetected variables for a change in patient movement, respiration rate,or pulse rate.
 51. The system of claim 1, further comprising: a humansupport structure supporting said fiber.
 52. The system of claim 1,further comprising: a human support structure adjacent said fiber. 53.The system of claim 1, further comprising: a mattress adjacent saidfiber.
 54. The system of claim 1, further comprising: a pad adjacentsaid fiber.
 55. The system of claim 1, further comprising: a carpetadjacent said fiber.
 56. The system of claim 1, wherein said systemcomprises an STM sensor.
 57. The system of claim 1, wherein said systemcomprises a HOME sensor.
 58. A method, comprising: transmitting from awireless digital photodetector coupled to an fiber optic sensor a signalencoding a plurality of detected variables of optical signals emergingfrom the fiber optic sensor; receiving the signal at a wirelessreceiver; decoding the signal at a signal processing module coupled to awireless receiver; and interpreting the plurality of detected variablesof the decoded signal.
 59. A method, comprising: spatially distributinga multimode optical fiber in a predetermined pattern for facilitatingsensing of a predetermined type of perturbation; transmitting opticalsignals from the spatially distributed integrating multimode opticalfiber; detecting the optical signals at a photodetector; and wirelesslytransmitting a wireless signal encoding a plurality of detectedvariables of the optical signals.
 60. The method of claim 59, furthercomprising: receiving the wireless signal at a wireless receiver. 61.The method of claim 59, further comprising: decoding the wirelesssignal.
 62. The method of claim 59, further comprising: decoding thewireless signal at a signal processing module coupled to a wirelessreceiver.
 63. The method of claim 59, further comprising: decrypting thewireless signal.
 64. The method of claim 59, further comprising:frequency despreading the wireless signal.
 65. The method of claim 59,further comprising: demodulating the wireless signal.
 66. The method ofclaim 59, further comprising: sampling the wireless signal.
 67. Themethod of claim 59, further comprising: digitizing the wireless signal.68. The method of claim 59, further comprising: detecting the wirelesssignal.
 69. The method of claim 59, further comprising: demultiplexingthe wireless signal.
 70. The method of claim 59, further comprising:spatially filtering the optical signals.
 71. The method of claim 59,further comprising: spatially filtering the wireless signal.
 72. Themethod of claim 59, further comprising: spatially filtering the detectedvariables.
 73. The method of claim 59, further comprising: Fouriertransforming the wireless signal.
 74. The method of claim 59, furthercomprising: interpreting the wireless signal.
 75. The method of claim59, further comprising: interpreting the plurality of detectedvariables.
 76. The method of claim 59, further comprising: monitoringthe wireless signal.
 77. The method of claim 59, further comprising:monitoring the plurality of detected variables.
 78. The method of claim59, further comprising: providing notification of a predetermined changein the wireless signal.
 79. The method of claim 59, further comprising:providing notification of a predetermined change in the plurality ofdetected variables.
 80. A machine-readable medium comprisinginstructions for activities comprising: decoding a wireless signalobtained from a wireless digital photodetector coupled to an opticalfiber spatial distributed in a predetermined pattern for facilitatingsensing of a predetermined type of perturbation, the wireless signalencoding a plurality of detected variables of optical signals emergingfrom the spatially distributed fiber optic sensor; and interpreting theplurality of detected variables of the decoded signal.